Interaction between Advanced Glycation End Products Formation and Vascular Responses in Femoral and Coronary Arteries from Exercised Diabetic Rats

Background: The majority of studies have investigated the effect of exercise training (TR) on vascular responses in diabetic animals (DB), but none evaluated nitric oxide (NO) and advanced glycation end products (AGEs) formation associated with oxidant and antioxidant activities in femoral and coronary arteries from trained diabetic rats. Our hypothesis was that 8-week TR would alter AGEs levels in type 1 diabetic rats ameliorating vascular responsiveness. Methodology/Principal Findings: Male Wistar rats were divided into control sedentary (C/SD), sedentary diabetic (SD/DB), and trained diabetic (TR/DB). DB was induced by streptozotocin (i.p.: 60 mg/kg). TR was performed for 60 min per day, 5 days/week, during 8 weeks. Concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP), phenylephrine (PHE) and tromboxane analog (U46619) were obtained. The protein expressions of eNOS, receptor for AGEs (RAGE), Cu/Zn-SOD and Mn-SOD were analyzed. Tissues NO production and reactive oxygen species (ROS) generation were evaluated. Plasma nitrate/nitrite (NOx-), superoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive substances (TBARS) and N-epsilon-(carboxymethyl) lysine (CML, AGE biomarker). A rightward shift in the concentration-response curves to ACh was observed in femoral and coronary arteries from SD/DB that was accompanied by an increase in TBARS and CML levels. Decreased in the eNOS expression, tissues NO production and NOx- levels were associated with increased ROS generation. A positive interaction between the beneficial effect of TR on the relaxing responses to ACh and the reduction in TBARS and CML levels were observed without changing in antioxidant activities. The eNOS protein expression, tissues NO production and ROS generation were fully re-established in TR/DB, but plasma NOx- levels were partially restored. Conclusion: Shear stress induced by TR fully restores the eNOS/NO pathway in both preparations from non-treated diabetic rats, however, a massive production of AGEs still affecting relaxing responses possibly involving other endothelium-dependent vasodilator agents, mainly in coronary artery.

Histological composition and progression of carotid plaque

Abstract Background To analyse histological composition and progression of carotid plaque. Methods Thirty-one patients (22 males, mean age 68.03 ± 7.3 years) admitted for carotid endarterectomy for extracranial high-grade internal carotid artery stenosis (≥ 70% luminal narrowing) were enrolled. The patients were divided into 2 groups according to symptomatology (group I, 17 symptomatic patients; and group II, 14 asymptomatic patients). A histological analysis and inflammatory cell quantification of each excised carotid plaque was made. Nine carotid arteries were removed from human cadavers that were not preselected for carotid artery disease. These specimens were used as a control tissue without any macroscopic signs of atherosclerotic plaques. Results Fifty eight percent of all carotid plaques were classified as complex plaque with possible surface defect, hemorrhage or thrombus. The inflammatory cells concentration did not differ between the two groups. All specimens from human cadavers were classified as preatheroma with extracellular lipid pools. Conclusion Asymptomatic and symptomatic patients could have the same histological components on their carotid plaques. Fibrotic and calcific plaques could become vulnerable as complex plaques with surface defect, hemorrhage and thrombus could remain silent. Asymptomatic carotid stenosis should be followed close with no invasive diagnostic methods and clinical evaluation.

Assessment of MMP-9, TIMP-1, and COX-2 in normal tissue and in advanced symptomatic and asymptomatic carotid plaques

Abstract Background Mature carotid plaques are complex structures, and their histological classification is challenging. The carotid plaques of asymptomatic and symptomatic patients could exhibit identical histological components. Objectives To investigate whether matrix metalloproteinase 9 (MMP-9), tissue inhibitor of MMP (TIMP), and cyclooxygenase-2 (COX-2) have different expression levels in advanced symptomatic carotid plaques, asymptomatic carotid plaques, and normal tissue. Methods Thirty patients admitted for carotid endarterectomy were selected. Each patient was assigned preoperatively to one of two groups: group I consisted of symptomatic patients (n = 16, 12 males, mean age 66.7 ± 6.8 years), and group II consisted of asymptomatic patients (n = 14, 8 males, mean age 67.6 ± 6.81 years). Nine normal carotid arteries were used as control. Tissue specimens were analyzed for fibromuscular, lipid and calcium contents. The expressions of MMP-9, TIMP-1 and COX-2 in each plaque were quantified. Results Fifty-eight percent of all carotid plaques were classified as Type VI according to the American Heart Association Committee on Vascular Lesions. The control carotid arteries all were classified as Type III. The median percentage of fibromuscular tissue was significantly greater in group II compared to group I (p < 0.05). The median percentage of lipid tissue had a tendency to be greater in group I than in group II (p = 0.057). The percentages of calcification were similar among the two groups. MMP-9 protein expression levels were significantly higher in group II and in the control group when compared with group I (p < 0.001). TIMP-1 expression levels were significantly higher in the control group and in group II when compared to group I, with statistical difference between control group and group I (p = 0.010). COX-2 expression levels did not differ among groups. There was no statistical correlation between MMP-9, COX-2, and TIMP-1 levels and fibrous tissue. Conclusions MMP-9 and TIMP-1 are present in all stages of atherosclerotic plaque progression, from normal tissue to advanced lesions. When sections of a plaque are analyzed without preselection, MMP-9 concentration is higher in normal tissues and asymptomatic surgical specimens than in symptomatic specimens, and TIMP-1 concentration is higher in normal tissue than in symptomatic specimens.

Morfologia dos vasos da base do encéfalo do quati (Nasua nasua)

Estudou-se a morfologia do encéfalo de Nasua nasua - quati, buscando comparar estes achados com outras espécies já descritos. Foram utilizados cinco encéfalos de quatis, provenientes do Criatório Científico (Cecrimpas), Unifeob. Os animais foram eutanásiados de acordo com a legislação (Cobea). Canulou-se a artéria carótida comum e a veia jugular externa sentido cranial, injetou-se solução de látex/bário corado de vermelho na artéria carótida, e solução de látex corado de azul na veia jugular. Em seguida os animais fixados em solução de formaldeído a 10%. O encéfalo tem sua nutrição dependente de quatro artérias, as artérias carótidas internas e as artérias vertebrais direitas e esquerdas. Esses vasos compuseram o circuito basilar e carotídeo que se anastomosam através das artérias cerebrais caudais. Correm na base do encéfalo sob a meninge pia mater.

Effect of simvastatin in the autonomic system is dependent on the increased gain/sensitivity of the baroreceptors

A number of mechanisms have been proposed to explain the pleiotropic effect of statin therapy to reduce sympathetic outflow in cardiovascular disease. We tested the hypothesis that statin treatment could improve baroreflex gain-sensitivity triggered by morphological adaptations in the mechanoreceptor site, thus reducing sympathetic activity, regardless of arterial pressure (AP) level reduction. Male spontaneously hypertensive rats (SHR) were divided into control (SHR, n = 8) and SHR-simvastatin (5 mg/kg/day, for 7 days) (SHR-S, n = 8). After treatment, AP, baroreflex sensitivity (BRS) in response to AP-induced changes, aortic depressor nerve activity, and spectral analyses of pulse interval (PI) and AP variabilities were performed. Internal and external carotids were prepared for morphoquantitative evaluation. Although AP was similar between groups, sympathetic modulation, represented by the low frequency band of PI (SHR: 6.84 ± 3.19 vs. SHR-S: 2.41 ± 0.96 msec2) and from systolic AP variability (SHR: 3.95 ± 0.36 vs. SHR-S: 2.86 ± 0.18 mmHg2), were reduced in treated animals. In parallel, simvastatin induced an increase of 26% and 21% in the number of elastic lamellae as well as a decrease of 9% and 25% in the carotid thickness in both, external and internal carotid, respectively. Moreover, improved baroreceptor function (SHR: 0.78 ± 0.03 vs. SHR-S: 1.06 ± 0.04% mv/mmHg) was observed in addition to a 115% increase in aortic depressor nerve activity in SHR-S rats. Therefore, our data suggest that the reduction of sympathetic outflow in hypertension by simvastatin treatment may be triggered by structural changes in the carotid arteries and increased BRS in response to an improvement of the baroreceptors discharge and consequently of the afferent pathway of the baroreflex arch.

Metformin, but not glimepiride, improves carotid artery diameter and blood flow in patients with type 2 diabetes mellitus

OBJECTIVE: To compare the effects of glimepiride and metformin on vascular reactivity, hemostatic factors and glucose and lipid profiles in patients with type 2 diabetes. METHODS: A prospective study was performed in 16 uncontrolled patients with diabetes previously treated with dietary intervention. The participants were randomized into metformin or glimepiride therapy groups. After four months, the patients were crossed over with no washout period to the alternative treatment for an additional four-month period on similar dosage schedules. The following variables were assessed before and after four months of each treatment: 1) fasting glycemia, insulin, catecholamines, lipid profiles and HbA(1) levels; 2) t-PA and PAI-1 (antigen and activity), platelet aggregation and fibrinogen and plasminogen levels; and 3) the flow indices of the carotid and brachial arteries. In addition, at the end of each period, a 12-hour metabolic profile was obtained after fasting and every 2 hours thereafter. RESULTS: Both therapies resulted in similar decreases in fasting glucose, triglyceride and norepinephrine levels, and they increased the fibrinolytic factor plasminogen but decreased t-PA activity. Metformin caused lower insulin and pro-insulin levels and higher glucagon levels and increased systolic carotid diameter and blood flow. Neither metformin nor glimepiride affected endothelial-dependent or endothelial-independent vasodilation of the brachial artery. CONCLUSIONS: Glimepiride and metformin were effective in improving glucose and lipid profiles and norepinephrine levels. Metformin afforded more protection against macrovascular diabetes complications, increased systolic carotid artery diameter and total and systolic blood flow, and decreased insulin levels. As both therapies increased plasminogen levels but reduced t-PA activity, a coagulation process was likely still ongoing.

Pulmonary root translocation in malposition of great arteries repair allows right ventricular outflow tract growth

Objective: Optimal surgical treatment of patients with transposition of the great arteries (TGA), ventricular septal defect (VSD), and pulmonary stenosis (PS) remains a matter of debate. This study evaluated the clinical outcome and right ventricle outflow tract performance in the long-term follow-up of patients subjected to pulmonary root translocation (PRT) as part of their surgical repair. Methods: From April 1994 to December 2010, we operated on 44 consecutive patients (median age, 11 months). All had malposition of the great arteries as follows: TGA with VSD and PS (n = 33); double-outlet right ventricle with subpulmonary VSD (n = 7); double-outlet right ventricle with atrioventricular septal defect (n = 1); and congenitally corrected TGA with VSD and PS (n 3). The surgical technique consisted of PRT from the left ventricle to the right ventricle after construction of an intraventricular tunnel that diverted blood flow from the left ventricle to the aorta. Results: The mean follow-up time was 72 +/- 52.1 months. There were 3 (6.8%) early deaths and 1 (2.3%) late death. Kaplan-Meier survival was 92.8% and reintervention-free survival was 82.9% at 12 years. Repeat echocardiographic data showed nonlinear growth of the pulmonary root and good performance of the valve at 10 years. Only 4 patients required reinterventions owing to right ventricular outflow tract problems. Conclusions: PRT is a good surgical alternative for treatment of patients with TGA complexes, VSD, and PS, with acceptable operative risk, high long-term survivals, and few reinterventions. Most patients had adequate pulmonary root growth and performance. (J Thorac Cardiovasc Surg 2012;143:1292-8)

The I405V and Taq1B polymorphisms of the CETP gene differentially affect sub-clinical carotid atherosclerosis

Background: Cholesteryl ester transfer protein (CETP) plays a major role in lipid metabolism, but studies on the association of CETP polymorphisms with risks of cardiovascular disease are inconsistent. This study investigated whether the CETP gene I405V and Taq1B polymorphisms modified subclinical atherosclerosis in an asymptomatic Brazilian population sample. Methods: The polymorphisms were analyzed using polymerase chain reaction in 207 adult volunteers. Serum lipid profiles, oxLDL Ab titers, C-reactive protein and tumor necrosis factor-a concentrations and CETP and phospholipid transfer protein (PLTP) activities were determined, and common carotid artery intima-media thickness (cIMT) was measured using ultrasonography. Results: No differences in cIMT were observed between the presence or absence of the minor B2 and V alleles in either polymorphism. However, inverse correlations between mean cIMT and CETP activity in the presence of these polymorphisms were observed, and positive correlations of these polymorphisms with PLTP activity and oxLDL Ab titers were identified. Moreover, logistic multivariate analysis revealed that the presence of the B2 allele was associated with a 5.1-fold (CI 95%, OR: 1.26 - 21.06) increased risk for cIMT, which was equal and above the 66th percentile and positively interacted with age. However, no associations with the V allele or CETP and PLTP activities were observed. Conclusions: None of the studied parameters, including CETP activity, explained the different relationships between these polymorphisms and cIMT, suggesting that other non-determined factors were affected by the genotypes and related to carotid atherosclerotic disease.

Assessment of Stent Strut Endothelialization in Iliac Arteries of Rabbits

Background: Fast post-implantation stent endothelialization is desirable for theoretically reducing the possibility of stent thrombosis. Objective: To evaluate the extent of sirolimus-eluting stent strut endothelialization (delivered from the luminal and abluminal aspects or abluminal aspect only) in the iliac arteries of rabbits. Methods: The iliac arteries of 10 rabbits were implanted with four sirolimus-eluting stents in the luminal and abluminal aspects, three sirolimus-eluting stents in the abluminal aspect, six polymer-coated stents, and four uncoated stents. After four weeks, the rabbits were euthanized and scanning electron microscopy was performed to quantify the area of exposed stent strut as well as the percentage of endothelialization. Results: The area (mean +/- SD) (mm(2)) of exposed uncoated stent struts, polymer-coated stents, sirulimus-eluting stent in the abluminal and luminal aspects and sirolimus-eluting stent in the abluminal aspect was 0.12 +/- 0.08, 0.09 +/- 0.12, 0.60 +/- 0.67 and 0.05 +/- 0.04, respectively (p = 0.120). The percentage of endothelialization (mean +/- SD) (%) of uncoated stents, polymer-coated stents, sirolimus-eluting stents in the luminal and abluminal aspects and sirolimus-eluting stents in the abluminal aspect was 99 +/- 01, 99 +/- 0. 97 +/- 03 and 99 +/- 0, respectively (p = 0.133). Conclusion: After four weeks of implantation in the iliac arteries of rabbits, both the sirolimus-eluting stents in the luminal plus abluminal aspects and those in the abluminal aspect only showed stent strut endothelialization rates similar to those of the other types of non-drug eluting stents. (Arq Bras Cardiol 2012;99(6):1123-1128)

Oxidized low-density lipoproteins and their antibodies: Relationships with the reverse cholesterol transport and carotid atherosclerosis in adults without cardiovascular diseases

Background: Metabolic predictors and the atherogenicity of oxidized LDL (oxLDL) and the specific antibodies against oxLDL (oxLDL Ab) are unclear and controversial. Methods: In 107 adults without atherosclerotic manifestations, we measured oxLDL and oxLDL Ab, and also the activities of CETP. PLTP, lipases and the carotid intima-media thickness (cIMT). Comparisons were performed for the studied parameters between the lowest and the highest tertile of oxLDL and oxLDL Ab, and the relationships between studied variables were evaluated. Results: Subjects with higher oxLDL Ab present reduced hepatic lipase activity and borderline increased cIMT. In the highest oxLDL tertile, besides the higher levels of total cholesterol, LDL-C and apoB100, we found reduced CETP activity and higher cIMT. A significant correlation between oxLDL Ab and cIMT, independent of oxLDL, and a borderline correlation between oxLDL and cIMT independent of oxLDL Ab were found. In the multivariate analysis, apoAl was a significant predictor of oxLDL Ab, in contrast to regulation of oxLDL by apoB100, PLTP and inverse of CETP. Conclusions: In adults without atherosclerotic disease, the metabolic regulation and carotid atherosclerosis of oxLDLAb and oxLDL groups, characterized a dual trait in oxLDL Ab, as a contributor to carotid atherosclerosis, much less so than oxidized LDL, and with a modest atheroprotective role. (C) 2012 Elsevier B.V. All rights reserved.

Endonasal endoscopic exposure of the internal carotid artery: An anatomical study

Objectives/Hypothesis: The aim of this work was to define the anatomical landmarks, limitations, and difficulties of obtaining internal carotid artery (ICA) exposure via endonasal endoscopic approaches (EEA).

Impaired beta-adrenoceptor-induced relaxation in small mesenteric arteries from DOCA-salt hypertensive rats is due to reduced K-Ca channel activity

beta-Adrenoceptor (beta-AR)-mediated relaxation plays an important role in the regulation of vascular tone. beta-AR-mediated vascular relaxation is reduced in various disease states and aging. We hypothesized that beta-AR-mediated vasodilatation is impaired in DOCA-salt hypertension due to alterations in the cAMP pathway. beta-AR-mediated relaxation was determined in small mesenteric arteries from DOCA-salt hypertensive and control uninephrectomized (Uni) rats. To exclude nitric oxide (NO) and cyclooxygenase (COX) pathways, relaxation responses were determined in the presence of L-NNA and indomethacin, NO synthase inhibitor and COX inhibitors, respectively. Isoprenaline (ISO)-induced relaxation was reduced in arteries from DOCA-salt compared to Uni rats. Protein kinase A (PKA) inhibitors (H89 or Rp-cAMPS) or adenylyl cyclase inhibitor (SQ22536) did not abolish the difference in ISO-induced relaxation between the groups. Forskolin (adenylyl cyclase activator)-induced relaxation was similar between the groups. The inhibition of IKCa/SKCa channels (TRAM-34 plus UCL1684) or BKCa channels (iberiotoxin) reduced ISO-induced relaxation only in Uni rats and abolished the relaxation differences between the groups. The expression of SKCa channel was decreased in DOCA-salt arteries. The expression of BKCa channel a subunit was increased whereas the expression of BKCa channel p subunit was decreased in DOCA-salt arteries. The expression of receptor for activated C kinase 1 (RACK1), which is a binding protein for BKG, channel and negatively modulates its activity, was increased in DOCA-salt arteries. These results suggest that the impairment of beta-AR-mediated relaxation in DOCA-salt mesenteric arteries may be attributable to altered IKCa/SKCa and/or BKCa channels activities rather than cAMP/PKA pathway. Impaired beta-AR-stimulated BKCa channel activity may be due to the imbalance between its subunit expressions and RACK1 upregulation. (C) 2012 Elsevier Ltd. All rights reserved.

The protective effect of cilostazol on isolated rabbit femoral arteries under conditions of ischemia and reperfusion: the role of the nitric oxide pathway

OBJECTIVES: The clinical significance of ischemia/reperfusion of the lower extremities demands further investigation to enable the development of more effective therapeutic alternatives. This study investigated the changes in the vascular reactivity of the rabbit femoral artery and nitric oxide metabolites under partial ischemia/reperfusion conditions following cilostazol administration. METHODS: Ischemia was induced using infrarenal aortic clamping. The animals were randomly divided into seven groups: Control 90 minutes, Ischemia/Reperfusion 90/60 minutes, Control 120 minutes, Ischemia/Reperfusion 120/90 minutes, Cilostazol, Cilostazol before Ischemia/Reperfusion 120/90 minutes, and Ischemia 120 minutes/Cilostazol/Reperfusion 90 minutes. Dose-response curves for sodium nitroprusside, acetylcholine, and the calcium ionophore A23187 were obtained in isolated femoral arteries. The levels of nitrites and nitrates in the plasma and skeletal muscle were determined using chemiluminescence. RESULTS: Acetylcholine- and A23187-induced relaxation was reduced in the Ischemia/Reperfusion 120/90 group, and treatment with cilostazol partially prevented this ischemia/reperfusion-induced endothelium impairment. Only cilostazol treatment increased plasma levels of nitrites and nitrates. An elevation in the levels of nitrites and nitrates was observed in muscle tissues in the Ischemia/Reperfusion 120/90, Cilostazol/Ischemia/Reperfusion, and Ischemia/Cilostazol/Reperfusion groups. CONCLUSION: Hind limb ischemia/reperfusion yielded an impaired endothelium-dependent relaxation of the femoral artery. Furthermore, cilostazol administration prior to ischemia exerted a protective effect on endothelium-dependent vascular reactivity under ischemia/reperfusion conditions.

The role of reactive oxygen species in the modulation of the contraction induced by angiotensin II in carotid artery from diabetic rat

The modulation played by reactive oxygen species on the angiotensin II-induced contraction in type I-diabetic rat carotid was investigated. Concentration-response curves for angiotensin II were obtained in endothelium-intact or endothelium-denuded carotid from control or streptozotocin-induced diabetic rats, pre-treated with tiron (superoxide scavenger), PEG-catalase (hydrogen peroxide scavenger), dimethylthiourea (hydroxyl scavenger), apocynin [NAD(P) H oxidase inhibitor], SC560 (cyclooxygenase-1 inhibitor), SC236 (cyclooxygenase-2 inhibitor) or Y-27632 (Rho-kinase inhibitor). Reactive oxygen species were measured by flow cytometry in dihydroethidium (DHE)-loaded endothelial cells. Cyclooxygenase and AT1-receptor expression was assessed by immunohistochemistry. Diabetes increased the angiotensin II-induced contraction but reduced the agonist potency in rat carotid. Endothelium removal, tiron or apocynin restored the angiotensin II-induced contraction in diabetic rat carotid to control levels. PEG-catalase, DMTU or SC560 reduced the angiotensin II-induced contraction in diabetic rat carotid at the same extent. SC236 restored the angiotensin II potency in diabetic rat carotid. Y-27632 reduced the angiotensin II-induced contraction in endothelium-intact or -denuded diabetic rat carotid. Diabetes increased the DHE-fluorescence of carotid endothelial cells. Apocynin reduced the DHE-fluorescence of endothelial cells from diabetic rat carotid to control levels. Diabetes increased the muscular cyclooxygenase-2 expression but reduced the muscular AT1-receptor expression in rat carotid. In summary, hydroxyl radical, hydrogen peroxide and superoxide anion-derived from endothelial NAD(P) H oxidase mediate the hyperreactivity to angiotensin II in type I-diabetic rat carotid, involving the participation of cyclooxygenase-1 and Rho-kinase. Moreover, increased muscular cyclooxygenase-2 expression in type I-diabetic rat carotid seems to be related to the local reduced AT1-receptor expression and the reduced angiotensin II potency. (C) 2011 Elsevier B. V. All rights reserved.

Correlation between carotid bifurcation calcium burden on non-enhanced CT and percentage stenosis, as confirmed by digital subtraction angiography

Objectives: Previous evidence supports a direct relationship between the calcium burden (volume) on post-contrast CT with the percent internal carotid artery (ICA) stenosis at the carotid bifurcation. We sought to further investigate this relationship by comparing non-enhanced CT (NECT) and digital subtraction angiography (DSA). Methods: 50 patients (aged 41-82 years) were retrospectively identified who had undergone cervical NECT and DSA. A 64-multidetector array CT (MDCT) scanner was utilised and the images reviewed using preset window widths/levels (30/300) optimised to calcium, with the volumes measured via three-dimensional reconstructive software. Stenosis measurements were performed on DSA and luminal diameter stenoses >40% were considered "significant". Volume thresholds of 0.01, 0.03, 0.06, 0.09 and 0.12 cm(3) were utilised and Pearson's correlation coefficient (r) was calculated to correlate the calcium volume with percent stenosis. Results: Of 100 carotid bifurcations, 88 were available and of these 7 were significantly stenotic. The NECT calcium volume moderately correlated with percent stenosis on DSA r=0.53 (p<0.01). A moderate-strong correlation was found between the square root of calcium volume on NECT with percent stenosis on DSA (r=0.60, p<0.01). Via a receiver operating characteristic curve, 0.06 cm(3) was determined to be the best threshold (sensitivity 100%, specificity 90.1%, negative predictive value 100% and positive predictive value 46.7%) for detecting significant stenoses. Conclusion: This preliminary investigation confirms a correlation between carotid bifurcation calcium volume and percent ICA stenosis and is promising for the optimal threshold for stenosis detection. Future studies could utilise calcium volumes to create a "score" that could predict high grade stenosis.